Method and apparatus for manufacturing molded products

ABSTRACT

The present invention provides apparatuses and methods for producing molded products such as floor mats, including automotive floor mats. In one embodiment, a molding process is provided for producing a molded product using a mold having a lower plate and an upper plate. The molding process includes steps of filling a first cavity of the lower plate with a liquid molding material of a first color, placing the upper plate on top of the lower plate such that a convex portion of the upper plate extends into the first cavity of the lower plate and contacts the molding material in the lower plate, and curing the liquid molding material.

FIELD OF THE INVENTION

The present invention relates generally to a method and apparatus formanufacturing molded products. More specifically, embodiments of thepresent invention relate to an open-pore molding process and apparatusfor manufacturing molded products. In addition, embodiments of thepresent invention are directed to molded products, including floor mats,manufactured using processes of the present invention.

BACKGROUND OF THE INVENTION

Open-pore or open cavity molding processes for manufacturing moldedrubber or plastic products are known. In a typical prior art open cavitymolding process, a single piece mold having a concave portion formedtherein is filled with a liquid rubber or plastic material, and the moldis inserted in an oven to cure the material. After curing, the finishedproduct is removed from the mold. These open cavity molding processes ofthe prior art are relatively inexpensive and are particularly useful formanufacturing substantially flat thin products including floor mats,such as those typically used in automobiles and other vehicles. Intypical open cavity molding processes, a single color of material isused to make single color products.

Products manufactured using open cavity molding processes typically haveone smooth side, formed from the top surface of the material in themold, and one featured side having a number of contoured features formedtherein by contours in the bottom surface of the concave portion of themold. For typical floor mats manufactured using the prior art processesdescribed above, the bottom surface of the floor mat is substantiallysmooth, and the top surface has a number of contours or features thatprovide a textured surface.

For floor mats and other products, it is sometimes desirable to havefeatures formed on the top and bottom surfaces of the products, and toprovide products having multiple colors. While it is possible to producesuch products using processes other than open cavity molding, such asinjection molding, these other processes are typically more complex andtherefore more expensive than open cavity molding. It is also sometimesdesirable to incorporate fabric into a portion of the top surface of theproduct to provide, for example a carpeted section of a floor mat.

SUMMARY OF THE INVENTION

In one general aspect, the present invention features a molding processfor producing a molded product using a mold having a lower plate and anupper plate. The molding process includes steps of filling a firstcavity of the lower plate with a molding material of a first color,placing the upper plate on top of the lower plate such that a convexportion of the upper plate extends into the first cavity of the lowerplate and contacts the molding material in the lower plate, and curingthe molding material.

The convex portion of the upper plate can have a plurality of convexsections and a plurality of concave sections, and the convex portion ofthe upper plate can be placed in the material such that the convexsections contact the material and force the material to flow into theconcave sections of the upper plate. The step of curing can occur beforeor after the step of placing. The method can further include a step offilling a second cavity in the lower plate with a liquid moldingmaterial of a second color. The step of filling the second cavity can beperformed before the step of filling the first cavity. The method caninclude a step of adding carpet material to the molded product. Themethod can also include a step of clamping the upper plate to the lowerplate.

Another general aspect of the present invention is directed to anapparatus for producing a molded product using a material. The apparatusincludes a bottom plate having an upper mating surface. The upper matingsurface has a cavity to receive the material. The cavity has bottomsurface containing a plurality of concave areas to form contouredfeatures in a first surface of the molded product. The apparatus canfurther include a top plate having a top surface and a bottom matingsurface. The bottom mating surface can be constructed and arranged tomate with the upper mating surface of the bottom plate. The bottommating surface can have a convex section arranged to extend into thecavity to contact liquid material in the cavity. A bottom surface of theconvex section of the top plate can have a plurality of convex sectionsto contact the liquid material in the cavity to form features in asecond surface of the molded product. The top plate can have a pluralityof holes extending from the bottom surface of the convex section to thetop surface of the top plate. The holes and the convex sections of thetop plate can be constructed and arranged such that material in thecavity is forced into the holes by the convex sections. At least one ofthe convex sections on the top plate can be in the shape of a pyramidhaving four base edges forming a polygon, the polygon having four comerpoints, and one of the holes can be located at each comer point of thepyramid. The top surface of the top plate can have a concave sectionthat captures material forced through the holes by the convex sections.

Another general aspect of the present invention is directed to anapparatus for producing a molded floor mat. The molded floor mat has anupper surface and a lower surface. The apparatus includes means forforming concave and convex features on the upper surface of the floormat and means for forming convex features on the lower surface of thefloor mat.

The means for forming concave and convex features on the upper surfaceof the floor mat can include means for molding a first part of the uppersurface of the floor mat using a first color of material and means formolding a second part of the upper surface of the floor mat using asecond color of material. The apparatus can further include means foradding carpeting to the upper surface of the floor mat.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference is madeto the drawings which are incorporated herein by reference and in which:

FIG. 1 is a cross-sectional side view of a mold in accordance with oneembodiment of the present invention;

FIG. 2 shows area A of the mold of FIG. 1 in greater detail;

FIG. 3 is a top view of an automotive floor mat produced using the moldshown in FIG. 1;

FIG. 4 is a bottom view of the automotive floor mat of FIG. 3;

FIG. 5 is a cross-sectional side view taken along line 5—5 of theautomotive floor mat of FIG. 3;

FIG. 6 is a top view of a bottom plate used in the mold shown in FIG. 1;

FIG. 7 is a cross sectional side view taken along line 7—7 of the bottomplate shown in FIG. 6;

FIG. 8 is a bottom view of a top plate used in the mold shown in FIG. 1;

FIG. 9 shows an area B of the top plate of FIG. 8 in greater detail;

FIG. 10 shows a cross-sectional side view taken along line 10—10 of thetop plate of FIG. 8;

FIG. 11 shows an area C of the top plate of FIG. 10 in greater detail;

FIG. 12 is a flow chart of a method for producing molded products inaccordance with one embodiment of the present invention;

FIG. 13 is a top view of an automotive floor mat having carpet sectionsproduced using a method of the present invention;

FIG. 14 is a bottom view of the automotive floor mat of FIG. 13;

FIG. 15 is a cross-sectional side view taken along line 15—15 of theautomotive floor mat of FIG. 13;

FIG. 16 is a top view of a bottom plate used to produce the automotivefloor mat shown in FIG. 13;

FIG. 17 is a cross-sectional side view of the bottom plate of FIG. 16taken along line 17—17;

FIG. 18 is a top view of a top plate in accordance with one embodimentof the present invention having a hole through which material can beinjected;

FIG. 19 is a top view of a plug used with the top plate shown in FIG.18;

FIG. 20 is a cross-sectional side view of the plug of FIG. 19 takenalong line 20—20;

FIG. 21 is a cross-sectional side view of the top plate of FIG. 18 takenalong line 21—21;

FIG. 22 is a cross-sectional side view of a mold in accordance with oneembodiment of the present invention having clamping assemblies forclamping the top plate to the bottom plate;

FIG. 23 is a side view if a plunger used in the clamping assemblies ofFIG. 22;

FIG. 24 is a side view of a top insert of the clamping assemblies ofFIG. 22;

FIG. 25 is a bottom view of the top insert of FIG. 24;

FIG. 26 is a side view of a bottom insert of the clamping assemblies ofFIG. 22; and

FIG. 27 is a side view of one of the clamping assemblies of FIG. 22.

DETAILED DESCRIPTION

Embodiments of the present invention are described below with referenceto automobile floor mats. As understood by those skilled in the art, theprocesses and apparatuses described below may be used for manufacturingmolded products other than floor mats using a number of differentmaterials.

FIG. 1 is a cross-sectional side view of an open cavity mold 10 usedwith embodiments of the present invention. FIG. 2 shows a portion A ofthe open cavity mold 10 in greater detail. The open cavity mold 10includes a bottom plate 12 and a top plate 14. The bottom plate 12includes a concave section 16, and the top plate 14 includes a convexsection 18 that extends into the concave section 16 of the bottom plate.In the embodiment shown in FIG. 1, the mold 10 is designed for producingautomobile floor mats having an overall shape defined by the perimeterof the concave section 16. FIGS. 3-5 show an automobile floor mat 110produced using the mold 10.

FIG. 6 shows a top view of the bottom plate 12 of the open cavity mold10, and FIG. 7 shows a cross-sectional side view of the plate 12 takenalong line 7—7 of FIG. 6. Around the base of the cavity 12 are threeconcave rings 20, 22 and 24 that define three convex ridges 120, 122 and124 in the floor mat 110. As discussed below, in embodiments of thepresent invention, each of the rings 120, 122 and 124 may be made from adifferent color of material. On the bottom surface of the concavesection 16 of the bottom plate 12, are a rear section 31, a heel section32 and a front section 33 that respectively correspond to rear section131, heel section 132 and front section 133 of the floor mat 110.Contained within the rear section 31 and the front section 33 of thebottom plate are a number of octagon shaped convex sections 26 andsquare convex section 28 that form respectively concave sections 126 and128 in the floor mat 110. Disposed between each of the convex sections26 are concave wells 30 that form ridges 130 in the floor mat 110.Section 32 of bottom plate 12 has valleys 34 and ridges 36 thatrespectively form raised ribs 134 and channels 136 in the floor mat 110.

The top plate 14 will now be described in greater detail with referenceto FIGS. 8-11. The convex section of the top plate 18 is designed to fitwithin the concave section 16 of the bottom plate 12. The convex sectionhas a lower surface 38 having a number of contoured features containedtherein for forming corresponding contoured features in the floor mat110. The lower surface 38 has pyramid-shaped convex sections 40 that aredesigned to extend into material in the concave section of the bottomplate when the top plate is placed into the bottom plate as describedbelow in further detail. The pyramid-shaped convex sections 40 causeconcave sections 140 to be formed in the floor mat 110. At the bottomcomers of each of the pyramid-shaped convex sections are air holes 42that extend through the top plate 14 from the bottom surface 38 of theconvex section 18 to the top surface 19 of the convex section. Asdescribed below, each of the air holes allows air to exit the areabetween the top plate and the bottom plate as the top plate is loweredinto the bottom plate. In addition, the air holes 42 are designed to befilled with material to create nubs 142 on the bottom surface of thefloor mat 110.

The top plate 14 has an upper concave section 44 (see FIG. 1) on the topsurface of the top plate opposite the convex section 18. The upperconcave section forms a well for containing any excess material thatflows through the air slots 42 when the top plate is placed into thebottom plate.

A method 200 in accordance with one embodiment of the present inventionfor producing the floor mat 110 using the mold 10 will now be describedwith reference to FIG. 12. In a first step 202, the concave section 16of the bottom plate 12 is filled with a predetermined quantity of liquidrubber or plastic material. In one embodiment, the material used ispolyvinyl chloride. However in other embodiments, other materials suchas silicone can also be used. During the first step, the top plate 14 isseparated from the bottom plate. Next, in step 204, the top plate islowered into the bottom plate so that the convex section 18 contacts thematerial in the concave section 16. The pyramid-shaped convex sections40 on the bottom surface of the top plate contact the material as thetop plate is lowered, and any air trapped between the top plate and thebottom plate is evenly forced out of the air holes 42. As the top plateis lowered, the convex sections 40 force material to flow into the airholes 42.

In embodiments of the invention, the quantity of material used forfilling the lower plate is selected so that material completely fillsall of the air holes 42. If excess material is used, the excess materialflows into the upper concave section 44. After the top plate has beenlowered into the bottom plate, then in step 206, the mold 10 is placedinto an oven to cure the material in the mold. The temperature of theoven and the curing time used depend on the material selected and thetype of product being made. In some embodiments, the top plate isclamped to the bottom plate during the curing process to ensure that thetop plate does not move with respect to the bottom plate when thematerial is cured. After the curing time, the mold 10 is removed fromthe oven, and in step 208, the top plate is removed from the bottomplate. Next, in step 210, the product is removed from the lower plate.

It is sometimes desirable to add a second color to a molded product. Intypical prior art processes, a second color is added by painting themolded product after curing. In embodiments of the present invention, amaterial having a second color can be added by filling one or more ofthe rings 20, 22 and 24 with a material having the second color prior tostep 202 of the process 200. If the material used for the second color(or other additional colors) is less viscous than the material used forthe first color, then the first color may be poured directly on top ofthe second color in the mold. If the material used for the second coloris not more viscous than that used for the first color, then in oneembodiment, the second color is cured in the oven prior to adding thefirst color. The top plate may be placed on top of the bottom plate whenthe second color is cured.

As understood by one skilled in the art, products having more than twocolors can be produced using three or more different-colored materials,and the use of different-colored materials is not limited to the outerrings, but different-colored materials may be used in other areas of thebottom plate as well.

In embodiments of the present invention, the top plate and the bottomplate are made from aluminum, and can be manufactured relativelyinexpensively and quickly using well-known machining techniques. Inprior art injection molding techniques, the molds are typically madefrom steel and are considerably more expensive and require more time tomanufacture than the top plate and the bottom plate of embodiments ofthe present invention.

In embodiments of the molding process described above, the top plate isadded to the bottom plate prior to curing the material. In otherembodiments, the top plate may be placed into the bottom plate eitherafter the material is cured or after the material is partially cured. Inthese embodiments, it may be desirable to use clamps or a press to bringthe plates together and force the convex section of the top plate intothe material in the bottom plate.

The molding process described above provides several advantages andovercomes problems associated with prior art open cavity moldingprocesses. The use of the convex sections 40 and air holes 42 allows airto evenly escape to prevent the creation of undesirable air pockets inthe final product and also allows features such as nubs 142 to be formedon the bottom surface of a product. In typical prior art open cavitymolding processes, features are formed on either the top surface orbottom surface of a product, but not on both surfaces as in embodimentsof the present invention.

In the embodiments described above, pyramid-shaped convex sections 40are used to evenly force air from between the plates and to create thenubs 142. In other embodiments, convex sections having other shapes,such as hemispherical, can be used in place of the pyramid-shaped convexsections.

It is sometimes desirable to include carpeted sections in floor mats andother molded products. In another embodiment of the present invention, amethod and apparatus is provided for producing floor mats havingcarpeted sections. One embodiment of a carpeted floor mat 410 producedusing methods of the present invention is shown in FIGS. 13-15. Thecarpeted floor mat 410 is similar to floor mat 110 except that sections131 and 133 of floor mat 110 have been replaced by carpeted sections 431and 433 in floor mat 410. The method for producing the carpeted floormat 410 in accordance with the present invention is similar to themethod 200 described above with reference to FIG. 12 with a fewexceptions.

The bottom plate 12 used with method 200 is replaced with bottom plate312 shown in FIGS. 16 and 17 to produce the carpeted floor mat 410.Bottom plate 312 is similar to bottom plate 12 and has sections 331, 332and 333 corresponding to sections 31, 32 and 33 of bottom plate 12.Bottom plate 312 differs from bottom plate 12 in that sections 331 and333 do not contain wells and ridges as in sections 31 and 33. Sections331 and 333 are convex sections that create wells in the floor mat 410that contain carpeted sections 431 and 433.

Using bottom plate 312 and top plate 14, the carpeted floor mat can beproduced using method 200 with an additional step. After the floor matis removed from the mold in step 210, pieces of carpet, sized to fitwithin wells created by sections 331 and 333 of the bottom plate, areadhered to the bottom surface of the wells. The pieces of carpet may beadhered to the bottom surface of the wells using an adhesive or doublesided tape. Alternatively, the pieces of carpet may be sewn or rivetedinto the product. The pieces of carpet used to create the carpetedsections may be obtained from one of several carpet manufacturersdepending on the style carpeting that is desired.

In embodiments of the present invention, a second color of material canbe added to the carpeted floor mat 410 using the same method describedabove for floor mat 110. The second color of material can be chosen tomatch the color of the carpet sections used in the floor mat 410. In oneembodiment, an emblem, or some other feature, may be made from thesecond color, and the emblem may be positioned on the upper surface ofthe floor mat such that it extends through a hole in the carpetedsection.

As described above, when adding a second material having a second colorto a product, in some embodiments of the present invention, it may bedesirable to cure the second material prior to adding the first materialhaving the first color. In these embodiments, it may be desirable tocure the second material with the top plate in place over the bottomplate. In one embodiment of the present invention, which will now bedescribed with reference to FIGS. 18-21, a top plate 514 of an opencavity mold includes a removable plug 515 to allow filling the mold witha first color of material after the second color has been cured withoutremoving the top plate from the bottom plate. The top plate 514 issubstantially identical to the top plate 14 described above, except thatthe top plate 514 includes a hole 517 for receiving the plug 515. Thesame reference numbers are used to identify similar features of topplates 14 and 514. Top plate 514 is designed to mate with bottom plate12 in a manner similar to top plate 14.

A process in accordance with one embodiment of the present invention forusing the top plate 514 in conjunction with the bottom plate 12 tomanufacture molded products using a first material of a first color anda second material of a second color will now be described. With the topplate 514 removed from the bottom plate 12, the second material ispoured into one or more cavities in the top surface of the bottom plate.The top plate 514 is then placed on top of the bottom plate 12 and thecombination of the top plate and the bottom plate is placed in an ovento cure the second material in the mold. After the second material hasfully cured, or in some embodiments has partially cured, the combinationof the top plate and the bottom plate is removed from the oven. The plug515 is then removed from the top plate 514, and the first material isinjected into the hole 517. In some embodiments, to force the materialinto each of the holes 42, the material is injected into hole 517 usinga pressurized container having an outlet adapter designed to mate withthe top plate at the hole 517.

After the first material has been injected, the plug 515 is insertedback into the hole 517. The combination of the top plate and the bottomplate is then placed back into the oven to cure the first material.After curing, the product in the mold can be removed from the mold inthe same manner as described above, and if desired, carpet material canbe added to the product.

As understood by one skilled in the art, in embodiments of the presentinvention that utilize the top plate 514, more than two colors may beincorporated into products by filling additional cavities in the bottomplate with materials having additional colors.

As discussed above, in some embodiments of the present invention, it maybe desirable to clamp the bottom plate to the top plate prior to curingthe material. In one embodiment of the present invention, which will nowbe described with reference to FIGS. 22-27, clamping assemblies are usedto clamp the top plate 14 to the bottom plate 12. FIG. 22 shows across-sectional side view of the open cavity mold 10 with two clampingassemblies 600 and 602 incorporated into the mold. In FIG. 22, the topplate 14 of the mold 10 is split to show a first one of the clampingassemblies 600 in a disengaged position and to show a second one of theclamping assemblies 602 in an engaged position. The clamping assembly600 is described below and shown in further detail in FIGS. 23-27, itbeing understood that clamping assembly 602 is substantially identicalto clamping assembly 600. In embodiments of the present invention, thenumber of clamping assemblies used in open cavity molds may be more orless than two depending primarily on the size of the mold.

The clamping assembly 600 includes a top insert 610, a bottom insert612, and a plunger 614. The top insert 610 is mounted in a hole in thetop plate 14, and the bottom insert 612 is mounted in a hole in thebottom plate 12. The holes in the top and bottom plates for the insertsare in alignment, when the top and bottom plates are aligned. Theplunger 614 is disposed in the top insert and is movable between adisengaged position shown in solid lines in FIG. 27 and an engagedposition shown in dashed lines in FIG. 27. In one embodiment, the topinsert, bottom insert and plunger are made from steel, however in otherembodiments, different materials could be used.

The top insert 614 has four arcuate pliable tabs 620 that extend from acylindrical section 628. Each of the tabs 620 has a tapered end section630. The top insert includes a cylindrical hollow section 632. Inaddition, a substantially cylindrical hollow section 634 is formed bythe four tabs 620.

The plunger 614 includes a knob 638, a cylindrical shaft 640 and adisc-shaped end section 642. The shaft 640 has an outer diameter that isslightly less than the diameter of the cylindrical section 628 of thetop insert. The end section 642 has an outer diameter that is greaterthan the diameter of the cylindrical section 628, and slightly less thanthe diameter of the hollow section 634.

The bottom insert 612 is cylindrical shaped and includes a hollow innerchamber 644. The inner chamber 644 has an upper surface 646 that slopesinwardly from top to bottom, a middle surface 648 that slopes outwardlyfrom top to bottom and a lower vertical surface 650.

The clamping assembly 600 operates as follows. When the top plate 12 isto be lowered onto the bottom plate 14, the knob 638 is lifted to placethe plunger in the raised position. Clamping assembly 600 is shown withthe plunger 614 in the raised position in FIG. 22. As the top plate islowered onto the bottom plate, the tabs 620 of each top insert arelowered into the hollow chamber 644 of the corresponding bottom insert.When the tabs are lowered into the hollow chamber, the tapered endsection 630 of each tab contacts the sloped upper surface 646 of thebottom insert causing each of the tabs to move inward slightly. When thetabs are fully inserted into the hollow chamber, such that the taperedend sections are adjacent the vertical surface 650, the tabs return totheir original position. The plunger is then pushed downward to thelower position. Clamping assembly 602 is shown with the plunger 614 inthe lowered position in FIG. 22. With the plunger 614 in the loweredposition, the tabs are locked in place in the hollow chamber. Theplunger prevents the tabs from bending inwardly as is necessary to movethe tabs past the sloped upper surface 646.

When the top plate is to be removed from the bottom plate after curingof the material, the knobs of each of the clamping assemblies are liftedto the upper position. With the knobs lifted, the tabs can be removedfrom the hollow chamber to separate the top plate from the bottom plate.In one embodiment of the present invention, the knobs are designed tomate with automated handling equipment allowing the knobs to be movedbetween the upper position and the lower position using the automatedhandling equipment. In addition, the automated handling equipment can beused to lower the top plate onto the bottom plate and to lift the topplate from the bottom plate using the knobs.

In embodiments of the present invention described above, the materialused in molding processes has been described as liquid material. Asunderstood by those skilled in the art, the material used need not be inliquid form, but may be in paste form or some other form havingsufficient viscosity to fill all cavities in the top and bottom plates.

Having thus described at least one illustrative embodiment of theinvention, various alterations, modifications and improvements willreadily occur to those skilled in the art. Such alterations,modifications and improvements are intended to be within the scope andspirit of the invention. Accordingly, the foregoing description is byway of example only and is not intended as limiting. The invention'slimit is defined only in the following claims and the equivalentsthereto.

What is claimed is:
 1. A molding process for producing a molded floormat product using a mold having a lower plate and an upper plate, themolding process comprising steps of: filling a first cavity of the lowerplate with a molding material of a first color; after filling the firstcavity, placing the upper plate on top of the lower plate, the upperplate having a plurality of convex sections and a plurality of concavesections, the convex sections of the upper plate being placed in themolding material such that the convex sections contact the moldingmaterial and force the molding material to flow into the concavesections of the upper plate; and curing the molding material.
 2. Themolding process of claim 1, wherein the step of curing occurs after thestep of placing.
 3. The molding process of claim 1, wherein the step ofplacing occurs after the material is partially cured.
 4. The moldingprocess of claim 3, further comprising a step of filling a second cavityin the lower plate with a molding material of a second color.
 5. Themolding process of claim 4, wherein the step of filling the secondcavity is performed before the step of filling the first cavity.
 6. Themolding process of claim 5, further comprising a step of adding carpetmaterial to the molded product.
 7. The molding process of claim 1,further comprising a step of filling a second cavity in the lower platewith a liquid molding material of a second color.
 8. The molding processof claim 1, further comprising a step of adding carpet material to themolded product.
 9. The molding process of claim 1, wherein the step ofplacing the top plate on the bottom plate includes a step of forcing airfrom between the plates out holes in the top plate.
 10. The moldingprocess of claim 1, further comprising a step of clamping the top plateto the bottom plate.